Fault correlation analysis of CNC modular machine tools based on ISM-MICMAC

Modular machine tools, characterized by high automation and mechatronic integration, are susceptible to fault propagation risks due to functional interdependencies, where subsystem failures can destabilize the entire system. Therefore, fault correlation analysis and the identification of critical faulty subsystems are essential. The DEMATEL method, however, is unable to differentiate the importance of subsystems within the same category when classifying them by centrality and causality. To address this limitation, an ISM-MICMAC-based method is proposed. A graph model oriented by fault propagation is established, and through adjacency and reachability matrices, the propelling influence and inter-factor reliance are computed. dividing subsystems into direct, indirect, and root causes. Subsystem weights are used to compare their importance within the same quadrant. A hierarchical structure model is developed to visualize fault propagation pathways. By synthesizing these analyses, the method identifies the relative significance of each subsystem, uncovers complex interactions, and clarifies their roles in fault propagation. Applied to two years of on-site fault data from five CNC modular machine tools, the comparison with DEMATEL results validates the effectiveness of the proposed method.